Linksys wrt1900ac v2 wireless radio 2.4ghz not showing


I do not see the 2.4ghz radio. how can i concluded it is hardware problem or software problem?

Check the output of dmesg for error messages, try iwinfo radio0 scan (up to radio2).

1 Like

Did you just install or upgrade OpenWrt? Or did the problem arise randomly after you had been using OpenWrt for a while? Did you make any changes to your config or install or upgrade any packages?

1 Like

dmesg

<<Marvell Mac80211 Wireless PCIE Network Driver version 10.3.9.1>>
....
...
...
<6>[   10.220736] ieee80211 phy0: 2G disabled, 5G enabled
<6>[   10.225662] ieee80211 phy0: 4 TX antennas, 4 RX antennas

2G disabled that is the relevant log i saw in dmesg. question is how do i enable it? i don't even see an entry in luci to enable or disable

iwinfo radio0 scan

Only scans for radio0 but not for radio1 or radio2

I have been using openwrt for like 2 years. i have flipped couple of times by that i mean:
let's say i have OEM firmware partition 1 and Openwrt in partition 2 . i may have booted OEM firmware and re-flashed on top an old Openwrt version. i am not sure if i was supposed to format some partition before doing it. Apart from that i recently did a sysupgrade from 23.5 to 23.5.2.

in the last 2 years for the most part i never used the wireless radio except for a brief little period i used the 5ghz antenna as a wifi-extender and that's when i might have disable the 2.4ghz antenna but for the love of god i can't remember how i disabled it?!

Let's try regenerating your wireless config file:

rm /etc/config/wireless
wifi config
root@OpenWrt:~# rm /etc/config/wireless 
root@OpenWrt:~# cat /etc/config/wireless 
cat: can't open '/etc/config/wireless': No such file or directory
root@OpenWrt:~# wifi config
root@OpenWrt:~# cat /etc/config/wireless 

config wifi-device 'radio0'
	option type 'mac80211'
	option path 'soc/soc:pcie/pci0000:00/0000:00:01.0/0000:01:00.0'
	option channel '36'
	option band '5g'
	option htmode 'VHT80'
	option disabled '1'

config wifi-iface 'default_radio0'
	option device 'radio0'
	option network 'lan'
	option mode 'ap'
	option ssid 'OpenWrt'
	option encryption 'none'

cat /sys/kernel/debug/ieee80211/phy0/mwlwifi/info
Output:

driver name: mwlwifi
chip type: 88W8864
hw version: 7
driver version: 10.3.9.1
firmware version: 0x0702091a
power table loaded from dts: yes
firmware region code: 0x0
mac address: XX:XX:XX...
2g: disable
5g: enable
antenna: 4 4
irq number: 81
ap macid support: 0000ffff
sta macid support: 00010000
macid used: 00000000
radio: disable
iobase0: 0cc72a6f
iobase1: 93b34d20
tx limit: 768
rx limit: 256
qe trigger number: 0

Strange... I'm not sure why this is happening.

Maybe @slh has an idea.

That said...

What happens if you switch to the OEM partition... does the radio work?

That's actually much more interesting and weird. so i did that switching drill. then reset the OEM firmware to default. did some initial setup. after setup.
weirdness 1: i was supposed to see two different SSID one for 2.4ghz and another for 5ghz but only the 5ghz was broadcasted although the router webui showed both where ON.
weirdness 2: the radio was wpa2-psk with password set but in my cellphone it was open and i was able to connect and surf the internet :exploding_head:

That is super strange.
Maybe a sanity check -- make sure the radio drops when you unplug power from the AP (just in the unlikely event that you were actually connected to another device).

Yea i did that sanity check and i was connected to the one it was broadcasting :frowning:

Also, i have backup of my openwrt settings in a tar so i thought maybe it is because of some kind of old version settings vs new version settings issue therefore, i had reset and also re-flashed the firmware to default and still 2.4ghz radio was a no show!

i am very close to opening the cover and check the motherboard with my multi-meter and put some heat with my heat gun but wish i could get the schematics of the motherboard

The 2.4G radio issue is sounding more like a hardware issue... but that may or may not be a typical hardware failure. For example, it could be a damaged "ART" partition (that's the factory calibration data). Or another possibility is that there is a power problem -- maybe try replacing your power adapter with a new one (ideally with more current capacity than your current one has).

Yeah, long gone are the days when the schematics would be readily available for computer equipment... there aren't even service manuals published in any 'public' way for these devices. They're really considered disposable once something fails (part of that is pragmatic because it is difficult to replace components, especially anything in the RF domain which would thus require factory recalibration; part of it is the relative expense of rework makes it less worthwhile, and part of it is the lack of a financial benefit to the manufacturers to make these things serviceable vs buying a new one).

Feel free to probe around -- maybe you'll find a failing capacitor or similar. Be gentle with the heat. Don't expect much, though...

1 Like

Interesting you mention power adapter because the power adapter i am using is not the original one (since i lost it). i bought this guy https://www.amazon.ca/gp/product/B00KKQMZQ6/

I am also trying to understand what ART partition you are talking about: is it displayed here https://openwrt.org/toh/linksys/wrt1900ac#wrt1900ac_v2 ?

Do you happen to know what the original power supply's specs were? 12VDC, but at what current? your new adapter supplies up to 1.5A which may be sufficient, but maybe you need something like 2A or better?? I don't know off hand. And I don't want to encourage you to buy something that may not fix the problem.

I don't know where the calibration/art partition exists, but I would guess it is one of the ones listed there, yes. If something happened that overwrote or corrupted the data in that partition, the radio will not have valid calibration data and typically will not even initialize. But the details of how the art partition might have been damaged and/or exactly where it is in the mtd partition scheme would require a bit more knowledge of the specifics of that device (and/or deeper review of the boot logs). So I can't really answer that part.

wee bit under powered, especially for the radios, 12V3A, but an error would be expected in dmesg; right after an enable in attempted.

not necessarily.

If it came with a 3A adapter, you certainly could be running at the limit with the 1.5A one you are using now.. I don't know how much margin they spec'd into the original supply, but it's likely less than a 100% margin (i.e. an adapter with half the rating is likely not enough).

The back of the router it says 12v 3A. the replacement power adapter says 4A


oh... then it should be fine. The one you linked to earlier said 1.5A, but as I look at it again, that was the input side... I was looking at the image itself, not the specs on the page.

Unless that adapter is itself failing, I wouldn't expect it to cause any issues with the 2.4G radio.

@slh @anomeome any idea what's going on?

When comparing with the openwrt bootlog i see i am missing the phy1 device not sure why because i see the kernel is loading two pcie device:

dmesg:

<6>[    9.645637] <<Marvell Mac80211 Wireless PCIE Network Driver version 10.3.8.0-20181210>>
<6>[    9.653685] pci 0000:00:01.0: enabling device (0140 -> 0142)
<7>[    9.659477] ieee80211 phy0: priv->pcmd_buf = (ptrval)  priv->pphys_cmd_buf = (ptrval)
<7>[    9.665024] ieee80211 phy0: fw download start
<5>[    9.665874] random: crng init done
<5>[    9.669290] random: 25 urandom warning(s) missed due to ratelimiting
<7>[    9.791538] ieee80211 phy0: FwSize = 118776 downloaded Size = 118776 curr_iteration 65497
<7>[   10.664977] ieee80211 phy0: fw download complete
<6>[   10.664990] ieee80211 phy0: device node: pcie@1,0
<7>[   10.670220] ieee80211 phy0: pcmd = a5d261d3
<6>[   10.688258] ieee80211 phy0: firmware version: 0x702091a
<6>[   10.710995] ieee80211 phy0: firmware region code: 0
<7>[   10.749117] ieee80211 phy0: regdomain: FCC
<7>[   10.749122] ieee80211 phy0: Channel: 36: 0x0 0x0 0xf
<7>[   10.749128] ieee80211 phy0: 12 12 12 12 12 12 12 12 10 10 10 10 f f f f 
<7>[   10.749131] ieee80211 phy0: Channel: 40: 0x0 0x0 0xf
<7>[   10.749136] ieee80211 phy0: 16 16 16 16 16 16 16 16 16 16 16 16 f f f f 
<7>[   10.749139] ieee80211 phy0: Channel: 44: 0x0 0x0 0xf
<7>[   10.749144] ieee80211 phy0: 16 16 16 16 16 16 16 16 16 16 16 16 f f f f 
<7>[   10.749147] ieee80211 phy0: Channel: 48: 0x0 0x0 0xf
<7>[   10.749152] ieee80211 phy0: 16 16 16 16 16 16 16 16 16 16 16 16 f f f f 
<7>[   10.749155] ieee80211 phy0: Channel: 52: 0x0 0x0 0xf
<7>[   10.749160] ieee80211 phy0: 11 11 11 11 10 10 10 10 12 12 12 12 10 10 10 10 
<7>[   10.749162] ieee80211 phy0: Channel: 56: 0x0 0x0 0xf
<7>[   10.749168] ieee80211 phy0: 11 11 11 11 10 10 10 10 12 12 12 12 10 10 10 10 
<7>[   10.749170] ieee80211 phy0: Channel: 60: 0x0 0x0 0xf
<7>[   10.749176] ieee80211 phy0: 11 11 11 11 10 10 10 10 12 12 12 12 10 10 10 10 
<7>[   10.749178] ieee80211 phy0: Channel: 64: 0x0 0x0 0xf
<7>[   10.749183] ieee80211 phy0: 11 11 11 11 10 10 10 10 12 12 12 12 10 10 10 10 
<7>[   10.749186] ieee80211 phy0: Channel: 100: 0x0 0x0 0xf
<7>[   10.749191] ieee80211 phy0: 10 10 10 10 11 11 11 11 12 12 12 12 10 10 10 10 
<7>[   10.749194] ieee80211 phy0: Channel: 104: 0x0 0x0 0xf
<7>[   10.749199] ieee80211 phy0: 11 11 11 11 10 10 10 10 12 12 12 12 10 10 10 10 
<7>[   10.749202] ieee80211 phy0: Channel: 108: 0x0 0x0 0xf
<7>[   10.749207] ieee80211 phy0: 11 11 11 11 10 10 10 10 11 11 11 11 10 10 10 10 
<7>[   10.749210] ieee80211 phy0: Channel: 112: 0x0 0x0 0xf
<7>[   10.749215] ieee80211 phy0: 11 11 11 11 10 10 10 10 11 11 11 11 10 10 10 10 
<7>[   10.749217] ieee80211 phy0: Channel: 116: 0x0 0x0 0xf
<7>[   10.749223] ieee80211 phy0: 11 11 11 11 10 10 10 10 11 11 11 11 10 10 10 10 
<7>[   10.749225] ieee80211 phy0: Channel: 120: 0x0 0x0 0xf
<7>[   10.749230] ieee80211 phy0: 11 11 11 11 10 10 10 10 11 11 11 11 10 10 10 10 
<7>[   10.749233] ieee80211 phy0: Channel: 124: 0x0 0x0 0xf
<7>[   10.749239] ieee80211 phy0: 11 11 11 11 10 10 10 10 11 11 11 11 10 10 10 10 
<7>[   10.749241] ieee80211 phy0: Channel: 128: 0x0 0x0 0xf
<7>[   10.749246] ieee80211 phy0: 11 11 11 11 10 10 10 10 11 11 11 11 10 10 10 10 
<7>[   10.749249] ieee80211 phy0: Channel: 132: 0x0 0x0 0xf
<7>[   10.749254] ieee80211 phy0: 11 11 11 11 10 10 10 10 11 11 11 11 10 10 10 10 
<7>[   10.749257] ieee80211 phy0: Channel: 136: 0x0 0x0 0xf
<7>[   10.749262] ieee80211 phy0: 11 11 11 11 10 10 10 10 11 11 11 11 10 10 10 10 
<7>[   10.749265] ieee80211 phy0: Channel: 140: 0x0 0x0 0xf
<7>[   10.749270] ieee80211 phy0: 11 11 11 11 10 10 10 10 11 11 11 11 10 10 10 10 
<7>[   10.749273] ieee80211 phy0: Channel: 149: 0x0 0x0 0xf
<7>[   10.749278] ieee80211 phy0: 16 16 16 16 16 16 16 16 15 15 15 15 15 15 15 15 
<7>[   10.749280] ieee80211 phy0: Channel: 153: 0x0 0x0 0xf
<7>[   10.749286] ieee80211 phy0: 16 16 16 16 15 15 15 15 15 15 15 15 15 15 15 15 
<7>[   10.749288] ieee80211 phy0: Channel: 157: 0x0 0x0 0xf
<7>[   10.749293] ieee80211 phy0: 16 16 16 16 15 15 15 15 15 15 15 15 15 15 15 15 
<7>[   10.749296] ieee80211 phy0: Channel: 161: 0x0 0x0 0xf
<7>[   10.749301] ieee80211 phy0: 16 16 16 16 15 15 15 15 15 15 15 15 15 15 15 15 
<7>[   10.749304] ieee80211 phy0: Channel: 165: 0x0 0x0 0xf
<7>[   10.749309] ieee80211 phy0: 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 
<6>[   10.749943] ieee80211 phy0: 2G disabled, 5G enabled
<6>[   10.754844] ieee80211 phy0: 4 TX antennas, 4 RX antennas
<6>[   10.792457] xt_time: kernel timezone is -0000
<6>[   10.800496] PPP generic driver version 2.4.2
<6>[   10.805132] NET: Registered protocol family 24
<14>[   10.812095] kmodloader: done loading kernel modules from /etc/modules.d/*

Not sure why only 0000:00:01.0 is loaded whereas i can see the kernel takes a note of both the pcie devices but mwlwifi only loads one of them not the 0000:00:02.0 :

ls -l /sys/devices/platform/soc/soc:pcie/pci0000\:00/
drwxr-xr-x    4 root     root             0 Jan  1  1970 0000:00:01.0
drwxr-xr-x    3 root     root             0 Jan  1  1970 0000:00:02.0
drwxr-xr-x    3 root     root             0 Jan  1  1970 pci_bus
-rw-r--r--    1 root     root          4096 Mar 12 02:14 uevent```

AFAIK the wrt1900acv2 (and other Linksys mvebu/ mwlwifi devices) doesn't have wifi calibration data (ART) on the main system flash, I assume Linksys has gone the more traditional way of putting the calibration data on a dedicated flash chip on the WLAN card there (well, technically the card is dissolved onto the main PCB there, but you get the idea), so I wouldn't expect that to be the issue here.

I have no personal experience with mvebu/ mwlwifi myself, so I can only provide generic debugging advice, in the sense of starting with a factory reset/ default wireless configurations and then eventually testing the OEM firmware. Wireless cards tend to run quite hot these days (ac/ ax in particular), putting their components through quite some (thermal-) stress, so components (especially the analogue ones in the rf path) going bad isn't unexpected, especially considering the age of these devices.

Flashing the OEM firmware (and ideally confirming the PSU's voltage while operating - or temporarily replacing it with a known good PSU, if at hand) should provide a definitive answer to this question though. Especially on this hardware, it's the easiest was to be sure.

1 Like